[effects/dimscreen] Port to JavaScript
Summary:
The ported effect looks quite similar to the C++ version except one
thing: it works correctly when user activates/deactivates a full
screen effect, for example the Desktop Cube effect.
Other than that, there are no behavioral or visual differences.
Reviewers: KWin, davidedmundson
Reviewed By: KWin, davidedmundson
Subscribers: davidedmundson, kwin
Tags: KWin
Differential Revision: https://phabricator.kde.org/D16452